Association of regional epicardial right ventricular electrogram voltage amplitude and late gadolinium enhancement distribution on cardiac magnetic resonance in patients with arrhythmogenic right ventricular cardiomyopathy: Implications for ventricular tachycardia ablation

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d8762495e233">BACKGROUND</h5> <p id="P2">Criteria for identification of anatomic ventricular tachycardia (VT) substrates in arrhythmogenic right ventricular cardiomyopathy (ARVC) on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) are unclear. </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d8762495e238">OBJECTIVE</h5> <p id="P3">We sought to define a) the association of regional RV epicardial voltage amplitude with the distribution of LGE, and b) appropriate image signal intensity (SI) thresholds for VT substrate identification, in ARVC. </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d8762495e243">METHODS</h5> <p id="P4">Pre-procedural LGE-CMR and epicardial electrogram mapping were performed in 10 ARVC patients. The location of epicardial electrogram map points, obtained during sinus rhythm with intrinsic conduction or RV pacing, were retrospectively registered to the corresponding LGE image regions. Standardized SI z-scores (standard deviation distance from the mean) were calculated for each 10-mm region surrounding map points. </p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d8762495e248">RESULTS</h5> <p id="P5">In patient-clustered, generalized estimating equations models that included 3205 epicardial EAM points and corresponding SI measures, bipolar (−1.43 mV/z-score, <i>P</i> &lt; 0.001) and unipolar voltage amplitude (−1.22 mV/z-score, <i>P</i> &lt; 0.001) were associated with regional SI z-scores. In contrast to the QRS-LP interval ( <i>P</i> =0.362), the LP activation index (LPAI) defined as electrogram duration divided by QRS-LP was associated with regional SI z-scores ( <i>P</i> &lt; 0.001). SI z-score thresholds of &gt;0.05 [95% confidence interval (CI), −0.05–0.15] and &lt; −0.16 (95% CI, −0.26–0.06) corresponded to bipolar voltage measures &lt;0.5 and &gt;1.0 mV, respectively. </p> </div><div class="section"> <a class="named-anchor" id="S5"> <!-- named anchor --> </a> <h5 class="section-title" id="d8762495e265">CONCLUSION</h5> <p id="P6">Increased RV gadolinium uptake is associated with lower epicardial bipolar and unipolar electrogram voltage amplitude. Standardized LGE-CMR SI z-scores may augment pre-procedural planning for identification of low voltage zones and abnormal myocardium in ARVC. </p> </div>